This application claims the priority benefit of Japanese Patent Application No. 2000-365850, filed on Nov. 30, 2000, and entitled xe2x80x9cDisk Drive Apparatus, Hard Disk Drive, Filter and Method for Inspecting Disk Drive Apparatus.xe2x80x9d
1. Technical Field
The present invention relates to a disk drive apparatus such as a hard disk drive, and more particularly to a filter attaching structure for preventing the entrance of dust into the disk drive apparatus.
2. Description of the Related Art
The most commonly used hard disk drive (hereinafter referred to as a HDD) as data storage means for computers has structure in which a single or plurality of magnetic disks are disposed coaxially and driven by a spindle motor. Data reading and writing are done by magnetic heads provided in opposition to the magnetic disks. The magnetic heads are driven by an actuator (generally, by a voice coil motor (hereinafter referred to as a VCM)). The magnetic disks, the magnetic heads, and the actuator are stored in a case called a disk enclosure. The disk enclosure is constructed of an aluminum alloy base in the form of a thin box, and a top cover for scaling an opening of the base. A gasket is provided on the circumference of a surface of the top cover opposed to the base. The base and the top cover are assembled so that the gasket is pressed against the top face of the circumferential wall of the base. In this manner, the disk enclosure is hermetically sealed.
The temperature within the disk enclosure rises due to the influence of the high rotational speed of magnetic disks, etc. Here, assume that the air within the disk enclosure expands with a rise in temperature and leaks from the gasket to the outside. There is a possibility that if the temperature within the disk enclosure falls, the air within the disk enclosure will shrink and therefore air will enter the disk enclosure from the outside. At this time, if dust and evaporated organic or inorganic substance, contained in the entering air, get into the disk enclosure, the magnetic head will crash against the dust or the organic or inorganic substance solidified on the disk surface during use of HDD, which will destroy the magnetic head or the magnetic disk. To prevent the entrance of dust into the disk enclosure, the HDD has a filter provided on the top cover or base. This filter is called a breather filter. This breather filter becomes a flow passage in which the circulation between the internal air and the external air is created by the expansion and contraction of the air within the disk enclosure due to temperature rise and fall. The breather filter is used to reduce the entrance of dust or evaporated organic or inorganic substance from the outside, to the degree that device performance is not affected.
A conventional breather filter will be described with reference to the drawings. FIG. 7 is a plan view showing the lower surface of a top cover 100. In the top cover 100, the upper surface means a surface that is exposed to the outside when the disk enclosure is constructed, while the lower surface means a surface that faces the disk enclosure in opposition to the base. A gasket 101 is stuck on the circumference of the lower surface of the top cover 100 so that the disk enclosure is hermetically sealed. In addition, a breather filter 102 is stuck on the lower surface of the top cover 100 by adhesive double-coated tape. FIG. 7 also shows a perspective view of the breather filter 102. Note that in the breather filter 102 shown in FIG. 7, a surface on which the top cover 100 is stuck is upward.
FIG. 8 is an exploded perspective view of the breather filter 102. In the figure, a surface that is stuck on the top cover 100 is downward. As illustrated in FIG. 8, the breather filter 102 is constructed mainly of a filter case 103, a filter main body 104 to be housed in the filter case 103, and an air vent film 105 for covering the upper surface of the filter main body 104. FIG. 9 shows the upper surface (FIG. 9A) and lower surface (FIG. 9B) of the filter case 103.
In FIGS. 8 and 9, the filter case 103 is constructed of a circular bottom wall 103a, and a circumferential wall 103b extending upward from the circumference of the bottom wall 103a. The upper surface of the bottom wall 103a has an air vent groove 103a1, while the lower surface has an air vent groove 103a2. Note that the upper surface of the bottom wall 103a in the filter case 103 refers to a lower surface in FIG. 8, while the lower surface refers to an upper surface in FIG. 8. The air vent groove 103a1 formed in the upper surface of the bottom wall 103a is a circular arc groove with the center of the bottom wall 103a as its starting point and an air vent hole 103a3 passing through the bottom wall 103a as its terminating point. The air vent groove 103a2 formed in the lower surface of the bottom wall 103a has an air vent hole 103a3 as its starting point and the center of the bottom wall 103a as its terminating point. Thus, the air vent groove 103a1 and the air vent groove 103a2 are communicated with each other through the air vent hole 103a3.
Adhesive double-coated tape 106 is bonded on the upper surface of the bottom wall 103a of the filter case 103, and adhesive double-coated tape 107 is bonded on the lower surface. Therefore, the air vent groove 103a1 forms a closed space between itself and the adhesive double-coated tape 106. Similarly, the air vent groove 103a2 forms a closed space between itself and the adhesive double-coated tape 107. However, since through holes 106a and 107a are formed in the centers of the adhesive double-coated tapes 106 and 107, as shown in FIG. 8, portions corresponding to the through holes are in communication with the outside.
The filter main body 104 is housed within the filter case 103. When this occurs, the filter main body 104 is bonded and fixed by the adhesive double-coated tape 107 bonded on the lower surface of the bottom wall 103a. Then, the air vent film 105 is stuck on the upper surface (in FIG. 8) of the filter main body 104. In this manner, the components are integrated into the breather filter 102. The adhesive double-coated tape 107 bonded on the upper surface of the bottom wall 103a bonds the breather filter 102 on the top cover 100. This state is shown in FIGS. 10 and 11. That is, the centers of the through hole 100a formed in the top cover 100, the through hole 106a of the adhesive double-coated tape 106, and the breather filter 102 are aligned with one another, and the breather filter 102 is fixed to the top cover 100 by the adhesive double-coated tape 106.
When the air within the disk enclosure expands, air will flow out to the outside through the following path. That is, the air within the disk enclosure passes through the air vent film 105, the filter main body 104, the through hole 107a of the adhesive double-coated tape 107, the air vent groove 103a2, the air vent hole 103a3, the air vent groove 103a1, the through hole 106a of the adhesive double-coated tape 106, and the through hole 100a of the top cover 100 in the recited order and flows out to the outside. On the other hand, when the outside air flows into the disk enclosure because of a fall in the temperature within the disk enclosure, the outside air passes through the through hole 100a of the top cover 100, the through hole 106a of the adhesive double-coated tape 106, the air vent groove 103a1, the air vent hole 103a3, the air vent groove 103a2, the through hole 107a of the adhesive double-coated tape 107, the filter main body 104, and the air vent film 105 in the recited order. Therefore, even if the entering air contains dust or an evaporated organic or inorganic substance, the entrance of dust into the disk enclosure can be reduced to the degree that device performance is not affected, because the air passes through the filter main body 104 and air vent film 105 which have activated charcoal as their main component.
3. Problems to Be Solved by the Invention
In the conventional breather filter 102 described above, the step of sticking the filter on the top cover 100 requires the positioning operation of aligning the through hole 100a of the top cover 100 with the center of the breather filter 102. The positioning operation is manually performed and therefore the labor of the operation is desired to be alleviated.
In addition, in the case of disassembling the assembled HDD and cleaning the top cover 100, it is necessary to remove the breather filter 102 from the top cover 100. When removing the breather filter 102 from the top cover 100, the adhesive agent of the adhesive double-coated tape 106 will remain on the top cover 100 or breather filter 102. Therefore, if the adhesive agent is not removed, the top cover 100 or breather filter 102 cannot be reused. Particularly, since the breather filter 102 is small in size, the operation of removing the adhesive agent is not easy. If the cost for manufacturing the breather filter 102 is compared with the cost required for the adhesive-agent removing operation, it is difficult to reuse the breather filter 102 on which the adhesive agent has remained. Therefore, in the case where the adhesive agent remains on the breather filter 102, there are cases where the use of a new breather filter 102 results in reduced cost. When employing a new breather filter 102, the operation of positioning the adhesive double-coated tape 106 with respect to the breather filter 102 becomes necessary.
In view of the points described above, an object of the present invention is to alleviate the labor of the positioning operation when attaching the breather filter to the top cover. Another object of the invention is to prevent the residue of the adhesive agent when removing the breather filter from the top cover.
The aforementioned conventional filter requires a troublesome positioning operation, because the breather filter is fixed to the lower surface of the top cover by the use of adhesive double-coated tape. Hence, the present invention eliminates the troublesome positioning operation by forming a through hole in the top cover and inserting the breather filer into the hole. In addition, the top cover can be fixed by employing adhesive single-coated tape.
The disk drive apparatus of the present invention is constructed so that the filter is attached to the enclosure through the through hole formed in the enclosure. Consequently, a special positioning operation can be eliminated only by inserting the filter into the through hole. More specifically, the conventional structure requires the operation of positioning the through hole of the tope cover with respect to the center of the breather filter, whereas the present invention eliminates the conventional positioning operation because a portion of the filter is exposed to the outside through the enclosure.
The disk drive apparatus of the present invention can be constructed so that the filter is supported on the enclosure. In this case, the enclosure has a chamfered portion around the circumference of the through hole; the filter has a flange corresponding to the chamfered portion; and the flange is brought into contact with the chamfered portion. And in the case of adopting the construction, the filter can be fixed to the enclosure by sticking adhesive tape on a circumference of the flange and a circumference of the chamfered portion of the enclosure. Therefore the problem of the residue of an adhesive caused conventionally by adhesive double-coated tape can be eliminated, because the fixation of the filter is performed with adhesive single-coated tape.
However, the filter fixing structure in the present invention is not limited to the case mentioned above. The fixation can also be performed only with adhesive tape, without forming a chamfered portion in the enclosure and a flange in the filter. In addition, in the present invention, a position at which the filter is provided is arbitrary. For example, the enclosure of a HDD is usually constructed of a top cover and a base, and in that case, the filter may be provided on either the top cover or the base.
In accordance with the present invention, there is provided a hard disk drive comprising: a magnetic disk for magnetically storing data; a spindle motor for spinning the magnetic disk; a rotary actuator rotatable around a pivot having a magnetic head for reading out or writing data from or to the magnetic disk, for locating the magnetic head over a desired track on the magnetic disk; a disk enclosure, including a box-shaped base with a hole and a cover for sealing the hole, for housing the magnetic disk, the spindle motor, and the rotary actuator; and a breather filter disposed so that it penetrates the cover.
In the hard disk drive of the present invention, the breather filter is disposed to penetrate the cover constituting the disk enclosure. Consequently, the present invention eliminates the conventional operation of positioning the through hole of the cover with respect to the center of the breather filter because the breather filter can be exposed to the outside through the cover.
Preferred forms of the hard disk drive of the present invention are as follows. The cover has a through hole which the breather filter penetrates, and an inclined surface which is provided in circumference of the cover and inclines toward the through hole. Also, the breather filter is a cylindrical breather filter having at one end surface thereof a stopper pawl which abuts the inclined surface. In addition, the breather filter penetrates the through hole of the cover so that the stopper pawl is held on the inclined surface. According to this form, there is no possibility that the breather filter will fall into the disk enclosure, because the breather filter is supported mechanically on the top cover. In addition, the stopper pawl of the breather filter abuts the inclined surface, so that the surface of the top cover can be prevented from becoming uneven.
In the hard disk drive of the present invention, one end surface of the breather filter is exposed to the outside through the cover and the remaining portion is positioned within the disk enclosure. Consequently, the breather filter can be removed with the disk enclosure constructed. On the other hand, in the conventional breather filter, the entire filter is disposed within the enclosure, so the top cover and the base must be separated in order to remove the breather filter.
In the hard disk drive of the present invention, the one end surface of the breather filter has an air vent hole through which the air within the disk enclosure or the outside air is discharged or introduced; and the breather filter, excluding the air vent hole, is applied by adhesive tape from the circumference side of the cover. Since the adhesive tape in this case is adhesive single-coated tape, the problem of the residue of the adhesive agent can be avoided in removing the breather filter from the top cover.
In accordance with the present invention, there is provided a filter for preventing the entrance of dust into a disk drive apparatus, comprising: a filter main body for filtering the dust; and a filter case with a portion for housing the filter main body; wherein the filter case includes a bottom wall, a side wall extending upward from a circumference of the bottom wall, and a flange formed on a circumference of the bottom wall, the housing portion being formed by the bottom wall and the side wall.
When the filter of the present invention is attached to the enclosure through the through hole formed in the enclosure of the disk drive apparatus, the flange can be held on the enclosure portion around the through hole.
In the filter of the present invention, wherein a path for circulating air is formed in a surface of the bottom wall which faces the housing portion, the path being constructed of a groove extending from the circumference of the bottom wall toward the center of the bottom wall. When air flows into the disk drive apparatus, the air circulates from the circumferential side to the center and then reaches the filter main body. In addition, the bottom wall is able to have an air vent hole, which penetrates the bottom wall and reaches the circulation path on the circumferential side.
In the disk drive according to the present invention, whether or not the filter is appropriately attached to the enclosure can be determined by measuring the pressure within the enclosure. Furthermore, in accordance with the present invention, there is provided a method for inspecting a disk drive apparatus equipped with a disk medium for storing data, an enclosure for housing a head for reading out or writing data from or to the disk medium, and a filter attached via a through hole provided in the enclosure. In summary, the method comprises the steps of: pressurizing or decompressing the enclosure through the filter, measuring pressure within the enclosure, and judging, based on a value of the measured pressure, whether or not the filter has been appropriately attached.